Part of the reason for the price cuts is that carmakers are not moving enough of these three cars to meet their legal requirements under California's zero-emission vehicle laws.

The fines are substantial, and would cost them far more than boosting the incentives on these so-called compliance cars.

However, all three are compliance cars whose sales are largely restricted to California--and, in a quirk of the law, the dozen or so other states that have adopted California's tougher emissions laws, including Oregon and a handful of Northeastern states.

The dealer priced the Volt (with a manufacturer suggested retail price of $43,000) at $36,751. McDonald got $2,000 cash back, paid $2,573 in sales tax, $170 documentation fee, $460 in gap insurance, and so ended up financing (at 0%) a total of $37,495 with no money down.

The car qualifies for a $7,500 Federal income-tax credit for which McDonald may be eligible when he files his 2013 taxes early next year.

Others available?

McDonald notes he saw a 2013 Volt advertised at $33,800 before taxes at a dealer in Columbus, Ohio. When he called Byers Chevrolet, he was told on the phone that they had another Volt for $32,495.

Note to Californians: These Volts may not have the emissions package that qualifies the car to receive a "green sticker" for single-occupancy access to the state's high-occupancy vehicle carpool lanes.

As always, read any offer from a car dealer carefully and make sure you understand all the financing, fees, and discounts before you sign anything.